Real time operating system for safety critical applications

Paul Boughton

The TQ Group has ported the INTEGRITY real time operating system to its TQMa6x minimodule for safety critical embedded applications, writes Nick Flaherty.

The minimodule is based on the i.Mx6 from Freescale Semiconductor (now part of NXP) and the port of the INTEGRITY RTOS from Green Hills Software. is designed to meet the highest requirements regarding safety and reliability. The INTEGRITY RTOS, certified to IEC 61508 SIL 3 and EN 50128 SWSIL 4, is an operating system with a hard real-time, high performance, partitioned architecture with guaranteed resource availability and advanced multicore support.

This provides safe separation between applications and guarantees non-interference between applications. Applications can be run with multiple levels of safety on the same processor, or separate certifiable components from non-certifiable components to minimise certification cost.

INTEGRITY provides secure partitioning provides protection from external attacks without degradation of the real-time performance or processor capacity. Green Hills Software has also pre-integrated an extensive range of middleware, which saves the developers valuable time and money in project implementation and is supported by the MULTI integrated development environment (IDE) certified to IEC 61508 SIL 4, EN 50128 SWSIL 4 and ISO 26262 ASIL D. The i.MX6 has both 2D and 3D GPUs that are also fully supported by INTEGRITY.

The combination of reliable hardware from TQ with the INTEGRITY real-time operating system from Green Hills Software forms a solid basis for applications with safety requirements up to SIL 4. Even if adjustments are made for customer projects, the board support package (BSP) forms an acceptable basis for future developments.

The rich and versatile set of peripherals integrated on the module makes it the ideal platform for a variety of application, specifically those taking advantage of virtualisation. The four ARM Cortex-A9 cores with a variable clock speed of up to 1GHz offer the tradeoff of performance and power for a particular application. Working memory with up to 2 Gbytes DDR3L and up to 128 Mbytes SPI NOR Flash, as well as up to 16GB eMMC Flash for program and data, is implemented on the TQMa6x, along with an EEPROM, an RTC and a real-time clock battery buffered from the main board.

All external usable signals of the CPU are available on the TQMa6x module via three cable connectors (2x160 + 1x40 pins) in the 0.8 mm grid.

For medical, automation, railway or shipping applications, the module with its long-term availability, which is also available for the INTEGRITY RTOS and MULTI IDE. The next collaboration with the INTEGRITY RTOS will be on the TQMLS102xA Layerscape module and should be available by the end of the first quarter of 2016.